One thing I've learned by being a "smart person" is that intelligence is not everything. I do not believe that high intelligence or even super-intelligence would automatically yield power, wealth, influence, or anything else that we might fear, especially if it has a high chance of coming with various forms of baggage and trade-offs.

We can't assume that the apparent correlation between intelligence and mental illness would hold in non-humans -- or that it wouldn't. That's because we don't understand why that correlation exists. But there is one trade-off that I think is likely to be universal: the smarter you are, the more effort you seem to have to put into "meta" thinking like philosophy to keep yourself on track.

Think of it this way: it's easy to drive a Honda Civic, but a supercar can actually require performance driving classes to learn to drive it safely. Otherwise you can do things like accelerate into the car in front of you very easily, lose control, etc. because it does not drive like a commodity car.

Many people with very high IQs use their high intelligence to create elaborate delusions and rationalizations that land them in a ditch. That's a "meta" problem, a philosophical problem, not a problem with engine size, but it's one that probably gets worse as the motor gets bigger.

It's another factor that I think might place rate limits on the rate at which an AI could self-improve. Technically it's just a special case of the combinatorial search problem associated with improving intelligence beyond known local maxima.

An AI just thinking "hey I can just double my processing power and storage and get twice as smart!" might very easily end in some novel form of madness, not super-intelligence.